Direction of Arrival Angle Estimation Using Non-Uniform Search Space
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing radar systems face challenges in accurately determining the directions of arrival angles for multiple targets using deterministic Maximum-Likelihood (DML) Direction-of-Arrival (DoA) estimation, particularly due to computational intensity and limitations in handling non-uniform distributions of target angles.
Innovation Solution
The proposed apparatus and method utilize a processor to receive radar signal datasets, define matrices of direction-of-arrival-angle vectors, and search for optimal sets of arrival angles by evaluating an objective function over a non-uniform search space. This approach includes the use of look-up tables for efficient correlation calculations and matrix operations, reducing computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If deterministic Maximum-Likelihood (DML) Direction-of-Arrival (DoA) estimation is used to determine directions of arrival angles for multiple targets, then measurement precision is improved, but device complexity and computational intensity increase
Solution Approach 1:
The patent segments the search space into discrete points parameterized by sin(θk), transforming the continuous DoA estimation problem into a discrete optimization problem. This segmentation allows the complex DML estimation to be performed over a finite set of candidate angles, reducing computational complexity while maintaining estimation accuracy.
Solution Approach 2:
The patent changes the parameterization of the search space from uniform angular spacing to non-uniform spacing based on sin(θk). This parameter transformation consolidates multiple local maxima into fewer discrete points, reducing the number of evaluations required while preserving the ability to accurately estimate DoA angles across the full search space.
2Device complexity
If a uniform search space is used for direction of arrival angle estimation, then device complexity is reduced, but measurement precision deteriorates for non-uniform target angle distributions
Solution Approach 1:
The patent applies local quality by creating a non-uniform search space where discrete points are distributed according to sin(θk). This results in denser sampling in regions where DoA angles are more likely to occur (near the boresight) and sparser sampling in less likely regions, optimizing the balance between computational efficiency and estimation accuracy for typical radar scenarios.
Solution Approach 2:
The patent transforms the search space parameter from uniform angular increments to non-uniform increments based on the sine function. This parameter change consolidates multiple local maxima into fewer discrete points, reducing the number of evaluations required while preserving the ability to accurately estimate DoA angles across the full search space.
3Measurement precision
If a non-uniform search space with non-uniform distribution of discrete points is used, then measurement precision is improved for non-uniform target angle distributions, but device complexity increases
Solution Approach 1:
The patent changes the parameterization of the search space from uniform angular spacing to non-uniform spacing based on sin(θk). This parameter transformation consolidates multiple local maxima into fewer discrete points, reducing the number of evaluations required while maintaining estimation accuracy.
Solution Approach 2:
The patent performs preliminary action by pre-calculating and storing the non-uniformly spaced discrete points and their corresponding sin(θk) values in a data structure before the DoA estimation process. This allows the estimation algorithm to directly query pre-computed values during execution, avoiding real-time complex calculations and reducing operational complexity.
Data Source
AI summary
An apparatus configured to receive an input dataset, x, indicative of radar signals reflected from targets as received at a plurality of antenna elements; define a matrix, A, formed of direction-of-arrival-angle vectors, an, each direction-of-arrival-angle vector representing an expected response at the plurality of antenna elements of radar signals from one of the targets; define a signal amplitude vector s to represent expected complex amplitudes as received in the radar signals; define an objective function based on x, A and s; search for a set of direction of arrival angles for each of the plurality of targets by the repeated evaluation of the objective function for a plurality of candidate matrices based on matrix A; and wherein said search space comprises a plurality of discrete points, z, associated with the direction of arrival angles by a function of sin(θk).